Radiation hardened composite layer plate or film

ABSTRACT

The invention relates to a radiation-curable laminated sheet or film comprising at least one substrate layer and a top layer which comprises a radiation-curable material having a glass transition temperature below 50° C. and having a high double bond density, processes for the production thereof and the use thereof.

The invention relates to a radiation-curable laminated sheet or filmcomprising at least one substrate layer and at least one top layer whichcomprises a radiation-curable material having a glass transitiontemperature below 50° C. and a high double bond density.

The application furthermore relates to a process for the production ofradiation-curable laminated sheets or films and a process for theproduction of shaped articles which are laminated with this sheet orfilm and the use thereof.

EP-A2 819 516 and EP-A2 819 520 disclose coated films, the coatinghaving a glass transition temperature below 40° C. and it being possiblefor the binder to be, for example, a phosphazene resin, urethanes oracrylates. The curing has to be carried out in two steps. Beforeadhesive bonding of the film to the substrates, partial curing iseffected and the final curing is carried out only thereafter.

EP-A-361 351 likewise discloses a coated film. Here, the radiationcuring of the film is effected before the application of the film to theshaped articles to be laminated.

EP-A2 874 027 discloses electron flash-curable compositions comprisingtwo components, the first of which is a monofunctional radiation-curablecompound whose homopolymer has a glass transition temperature of 20° C.or more and the second of which is a di(meth)acrylate, in the ratio10:90-90:10. A higher-functional acrylate can optionally also be mixedwith such compositions.

Disadvantageous thereby is the fact that the monofunctional(meth)acrylates often have high volatility owing to their low molecularweight which, owing to the general toxicity of (meth)acrylates, makesthe uncured coating material unsafe with regard to health. Moreover, theuse of monofunctional (meth)acrylates leads only to a low crosslinkingdensity, which however is desired for positive coating properties.

The fact that the radiation curing often has to be carried out in aplurality of steps, as described in EP-A2 819 546, is disadvantageous inthe case of the radiation-curable coated films known to date. In thecase of complete radiation curing of the film before the coatingprocess, the film often becomes brittle and difficult to shape, which isdisadvantageous for the further processing of the film.

WO 00/63015 discloses laminated sheets or films which have a top layerhaving a glass transition temperature above 40° C. and a double bonddensity of up to 0.2 mol/100 g. The poor scratch resistance thereof andonly a low gloss are disadvantages of such laminated sheets.

Radiation-curable laminated sheets or films which can be readilyprocessed and can be used by as simple methods as possible forlamination with shaped articles were therefore an object of theinvention. The laminated shaped articles should have good mechanicalproperties and good resistances to external influences and in particularshould be stable to mechanical effects, for example should have improvedscratch resistance, have high resilience and additionally have improvedoptical properties, such as, for example, increased gloss.

Accordingly, radiation-curable laminated sheets or films comprising atleast one substrate layer and at least one top layer for lamination withshaped articles were found, the top layer consisting of aradiation-curable material which contains a binder having a glasstransition temperature below 50° C. and a content of ethylenicallyunsaturated groups of more than 2 mol/kg of binder, referred to below asfilm for short.

Processes for the lamination of shaped articles with the film, and thelaminated shaped articles, were also found.

The film has to consist of a substrate layer and a top layer which isapplied directly or, if further intermediate layers are present,indirectly to the substrate layer.

Top Layer

The top layer is radiation-curable. The top layer used is therefore aradiation-curable material which comprises groups curable by a freeradical or ionic method (curable groups for short). Groups curable by afree radical method are preferred.

The radiation-curable material is preferably transparent. Even aftercuring is complete, the top layer is preferably transparent, i.e. it isa clear coat.

A substantial component of the radiation-curable material is the binder,which forms the top layer by film formation.

The radiation-curable material preferably comprises at least one binderselected from the group consisting of

-   i) polymers having ethylenically unsaturated groups and having an    average molar mass M_(n) of more than 2000 g/mol-   ii) mixtures of i) with ethylenically unsaturated, low molecular    weight compounds differing from i) and having a molar mass of less    than 2000 g/mol-   iii) mixtures of saturated thermoplastic polymers with ethylenically    unsaturated compounds.

Re i)

Suitable polymers are, for example, polymers of ethylenicallyunsaturated compounds but also polyesters, polyethers, polycarbonates,polyepoxides or polyurethanes having a molar mass of more than 2000g/mol.

For example, unsaturated polyester resins which substantially comprisepolyols, in particular diols, and polycarboxylic acid, in particulardicarboxylic acid, are suitable, one of the esterification componentscomprising a copolymerizable, ethylenically unsaturated group. Forexample, this is maleic acid, fumaric acid or maleic anhydride.

Polymers of ethylenically unsaturated compounds as obtained inparticular by free radical polymerization are preferred.

The polymers obtained by free radical polymerization are in particularpolymers which are composed of more than 40% by weight, particularlypreferably of more than 60% by weight, of acrylate monomers, inparticular C₁-C₈-alkyl (meth)acrylates, preferably C₁-C₄-alkyl(meth)acrylates, particularly preferably methyl (meth)acrylate, ethyl(meth)acrylate or n-butyl (meth)acrylate.

As ethylenically unsaturated groups, the polymers comprise, for example,vinyl ether and/or in particular (meth)acrylate groups. These may bebonded to the polymer, for example, by reaction of (meth)acrylic acidwith epoxide groups in the polymer (for example by the concomitant useof glycidyl (meth)acrylate as a comonomer).

Epoxide (meth)acrylates are obtainable by reacting epoxides with(meth)acrylic acid. Suitable epoxides are, for example, epoxidizedolefins, aromatic glycidyl ethers or aliphatic glycidyl ethers,preferably those of aromatic or aliphatic glycidyl ethers.

Epoxidized olefins may be, for example, ethylene oxide, propylene oxide,isobutylene oxide, 1-butene oxide, 2-butene oxide, vinyloxirane, styreneoxide or epichlorohydrin, preferably ethylene oxide, propylene oxide,isobutylene oxide, vinyloxirane, styrene oxide or epichlorohydrin,particularly preferably ethylene oxide, propylene oxide orepichlorohydrin and very particularly preferably ethylene oxide andepichlorohydrin. Aromatic glycidyl ethers are, for example, bisphenol Adiglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidylether, bisphenol S diglycidyl ether, hydroquinone diglycidyl ether,alkylation products of phenol/dicyclopentadiene, e.g.2,5-bis[(2,3-epoxypropoxy)phenyl]octahydro-4,7-methano-5H-indene) (CASNo. [13446-85-0]), tris[4-(2,3-epoxypropoxy)phenyl]methane isomers) (CASNo. [66072-39-7]), phenol-based epoxy novolaks (CAS No. [9003-35-4]) andcresol-based epoxy novolaks (CAS No. [37382-79-9]).

Aliphatic glycidyl ethers are, for example, 1,4-butanediol diglycidylether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidylether, pentaerythrityl tetraglycidyl ether,1,1,2,2-tetrakis[4-(2,3-epoxypropoxy)phenyl]ethane (CAS No.[27043-37-4]), diglycidyl ethers of polypropylene glycol(α,ω-bis(2,3-epoxypropoxy)poly(oxypropylene) (CAS No. [16096-30-3]) andof hydrogenated bisphenol A(2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane (CAS No. [13410-58-7]).

The epoxide (meth)acrylates and epoxide vinyl ethers preferably have anumber average molecular weight M_(n) of from 2000 to 20 000,particularly preferably from 2000 to 10 000, g/mol and very particularlypreferably from 2000 to 3000 g/mol; the content of (meth)acrylate andvinyl ether groups is preferably from 1 to 5, particularly preferablyfrom 2 to 4, per 1000 g of epoxide (meth)acrylate or vinyl ether epoxide(determined by gel permeation chromatography using polystyrene as astandard and tetrahydrofuran as an eluent).

Polyurethanes are likewise preferred. These likewise preferablycomprise, as unsaturated groups, (meth)acrylate groups which are bondedto the polyurethane, for example, by reaction of hydroxyalkyl(meth)acrylates with isocyanate groups.

Such urethane (meth)acrylates are obtainable, for example, by reactingpolyisocyanates with hydroxyalkyl (meth)acrylates or hydroxyalkyl vinylethers and, if appropriate, chain extenders, such as diols, polyols,diamines, polyamines or dithiols or polythiols. Urethane (meth)acrylatesdispersible in water without addition of emulsifiers additionallycontain ionic and/or nonionic hydrophilic groups, which are introducedinto the urethane, for example, by components such as hydroxcarboxylicacids.

The polyurethanes which can be used as binders substantially comprise ascomponents:

-   (a) at least one organic aliphatic, aromatic or cycloaliphatic di-    or polyisocyanate,-   (b) at least one compound having at least one group reactive toward    isocyanate and at least one unsaturated group capable of free    radical polymerization and-   (c) if appropriate, at least one compound having at least two groups    reactive toward isocyanate.

For example, aliphatic, aromatic and cycloaliphatic di- andpolyisocyanates having an NCO functionality of at least 1.8, preferablyfrom 1.8 to 5 and particularly preferably from 2 to 4, and theisocyanurates, biurets, allophanates and uretdiones thereof, aresuitable as component (a).

The diisocyanates are preferably isocyanates having 4 to 20 carbonatoms. Examples of conventional diisocyanates are aliphaticdiisocyanates, such as tetramethylene diisocyanate, hexamethylenediisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate,decamethylene diisocyanate, dodecamethylene diisocyanate,tetradecamethylene diisocyanate, derivatives of lysine diisocyanate,tetramethylxylylene diisocyanate, trimethylhexane diisocyanate ortetramethylhexane diisocyanate, cycloaliphatic diisocyanates, such as1,4-, 1,3- or 1,2-diisocyanatocyclohexane, 4,4′- or2,4′-di(isocyanatocyclohexyl)methane,1-isocyanato-3,3,5-trimethyl-5-(isocyanatomethyl)cyclohexane (isophoronediisocyanate), 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or 2,4- or2,6-diisocyanato-1-methylcyclohexane, and aromatic diisocyanates, suchas toluene 2,4- or 2,6-diisocyanate and the isomer mixtures thereof, m-or p-xylylene diisocyanate, 2,4′- or 4,4′-diisocyanatodiphenylmethaneand the isomer mixtures thereof, phenylene 1,3- or 1,4-diisocyanate,1-chlorophenylene 2,4-diisocyanate, naphthylene 1,5-diisocyanate,biphenylene 4,4′-diisocyanate, 4,4′-diisocyanato-3,3′-dimethylbiphenyl,3-methyldiphenylmethane 4,4′-diisocyanate, tetramethylxylylenediisocyanate, 1,4-diisocyanatobenzene or 4,4′-diisocyanatodiphenylether. Mixtures of said diisocyanates may also be present.

Hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane,isophorone diisocyanate and di(isocyanatocyclohexyl)methane arepreferred.

Suitable polyisocyanates are polyisocyanates having isocyanurate groups,uretdione diisocyanates and polyisocyanates having biuret groups,polyisocyanates having urethane or allophanate groups, polyisocyanatescomprising oxadiazinetrione groups, uretonimine-modified polyisocyanatesof linear or branched C₄-C₂₀-alkylene diisocyanates, cycloaliphaticdiisocyanates having in total 6 to 20 carbon atoms or aromaticdiisocyanates having in total 8 to 20 carbon atoms or mixtures thereof.

The di- and polyisocyanates which can be used preferably contain from 10to 60% by weight, based on the di- and polyisocyanate (mixture),preferably from 15 to 60% by weight and particularly preferably from 20to 55% by weight, of isocyanate groups (calculated as NCO, molecularweight=42).

Aliphatic or cycloaliphatic di- and polyisocyanates, for example theabove-mentioned aliphatic or cycloaliphatic diisocyanates, or mixturesthereof, are preferred.

The following are furthermore preferred:

-   1) Polyisocyanates having isocyanurate groups and obtained from    aromatic, aliphatic and/or cycloaliphatic diisocyanates.    Particularly preferred here are the corresponding aliphatic and/or    cycloaliphatic isocyanatoisocyanurates and in particular those based    on hexamethylene diisocyanate and isophorone diisocyanate. The    isocyanurates present are in particular trisisocyanatoalkyl or    trisisocyanatocycloalkyl isocyanurates, which are cyclic trimers of    the diisocyanates, or are mixtures with their higher homologs having    more than one isocyanurate ring. The isocyanatoisocyanurates    generally have an NCO content of from 10 to 30% by weight, in    particular from 15 to 25% by weight, and an average NCO    functionality of from 3 to 4.5.-   2) Uretdione diisocyanates having aromatically, aliphatically and/or    cycloaliphatically bonded isocyanate groups, preferably having    aliphatically and/or cycloaliphatically bonded groups and in    particular those derived from hexamethylene diisocyanate or    isophorone diisocyanate. Uretdione diisocyanates are cyclic    dimerization products of diisocyanates.    -   The uretdione diisocyanates can be used in the formulations as a        sole component or as a mixture with other polyisocyanates, in        particular those mentioned under 1).-   3) Polyisocyanates having biuret groups and having aromatically,    cycloaliphatically or aliphatically bonded, preferably    cycloaliphatically or aliphatically bonded, isocyanate groups, in    particular tris(6-isocyanatohexyl)biuret or mixtures thereof with    its higher homologs. These polyisocyanates having biuret groups    generally have an NCO content of from 18 to 22% by weight and an    average NCO functionality of from 3 to 4.5.-   4) Polyisocyanates having urethane and/or allophanate groups and    having aromatically, aliphatically or cycloaliphatically bonded,    preferably aliphatically or cycloaliphatically bonded, isocyanate    groups, as can be obtained, for example, by reaction of excess    amounts of hexamethylene diisocyanate or of isophorone diisocyanate    with polyhydric alcohols, such as, for example, trimethylolpropane,    neopentylglycol, pentaerythritol, 1,4-butanediol, 1,6-hexanediol,    1,3-propanediol, ethylene glycol, diethylene glycol, glycerol,    1,2-dihydroxypropane or mixtures thereof. These polyisocyanates    having urethane and/or allophanate groups generally have an NCO    content of from 12 to 20% by weight and an average NCO functionality    of from 2.5 to 3.-   5) Polyisocyanates comprising oxadiazinetrione groups, preferably    derived from hexamethylene diisocyanate or isophorone diisocyanate.    Such polyisocyanates comprising oxadiazinetrione groups can be    prepared from diisocyanate and carbon dioxide.-   6) Uretonimine-modified polyisocyanates.

The polyisocyanates 1) to 6) can be used as a mixture, if appropriatealso as a mixture with diisocyanates.

Compounds suitable as component (b) are those which carry at least onegroup reactive toward isocyanate and at least one group capable of freeradical polymerization.

Groups reactive toward isocyanates may be, for example, —OH, —SH, —NH₂and —NHR¹, where R¹ is hydrogen or an alkyl group comprising 1 to 4carbon atoms, such as, for example, methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl or tert-butyl.

Components (b) may be, for example, monoesters of α,β-unsaturatedcarboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid,itaconic acid, fumaric acid, maleic acid, acrylamidoglycolic acid ormethacrylamidoglycolic acid, or vinyl ethers with di- or polyols, whichpreferably have 2 to 20 carbon atoms and at least two hydroxyl groups,such as ethylene glycol, diethylene glycol, triethylene glycol,1,2-propylene glycol, 1,3-propylene glycol, 1,1-dimethyl-1,2-ethanediol,dipropylene glycol, triethylene glycol, tetraethylene glycol,pentaethylene glycol, tripropylene glycol, 1,4-butanediol,1,5-pentanediol, neopentylglycol, 1,6-hexanediol,2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol,1,4-dimethylolcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane,glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane,pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THFhaving a molecular weight of from 162 to 2000, poly-1,3-propanediolhaving a molecular weight of from 134 to 400 or polyethylene glycolhaving a molecular weight of from 238 to 458. It is furthermore possibleto use esters or amides of (meth)acrylic acid with amino alcohols, e.g.2-aminoethanol, 2-(methylamino)ethanol, 3-amino-1-propanol,1-amino-2-propanol or 2-(2-aminoethoxy)ethanol, 2-mercaptoethanol orpolyaminoalkanes, such as ethylenediamine or diethylenetriamine, orvinylacetic acid.

Unsaturated polyetherols or polyesterols or polyacrylatepolyols havingan average OH functionality of from 2 to 10 are furthermore suitable.

Examples of amides of ethylenically unsaturated carboxylic acids withamino alcohols are hydroxyalkyl(meth)acrylamides, such asN-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide,N-hydroxyethylacrylamide, N-hydroxyethyl-methacrylamide,5-hydroxy-3-oxapentyl(meth)acrylamide, N-hydroxyalkylcrotonamides, suchas N-hydroxymethylcrotonamide or N-hydroxyalkylmaleimides, such asN-hydroxyethylmaleimide.

2-Hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate,1,4-butanediol mono(meth)acrylate, neopentylglycol mono(meth)acrylate,1,5-pentanediol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate,glyceryl mono- and di(meth)acrylate, trimethylolpropane mono- anddi(meth)acrylate, pentaerythrityl mono-, di- and tri(meth)acrylate, and4-hydroxybutyl vinyl ether, 2-aminoethyl (meth)acrylate, 2-aminopropyl(meth)acrylate, 3-aminopropyl (meth)acrylate, 4-aminobutyl(meth)acrylate, 6-aminohexyl (meth)acrylate, 2-thioethyl (meth)acrylate,2-aminoethyl(meth)acrylamide, 2-aminopropyl(meth)acrylamide,3-aminopropyl-(meth)acrylamide, 2-hydroxyethyl(meth)acrylamide,2-hydroxypropyl(meth)acrylamide or 3-hydroxypropyl(meth)acrylamide arepreferably used. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2- or 3-hydroxypropyl acrylate, 1,4-butanediol monoacrylate and3-(acryloyloxy)-2-hydroxypropyl methacrylate are particularly preferred.

Compounds which are suitable as component (c) are those which have atleast two groups reactive toward isocyanate, for example —OH, —SH, —NH₂or —NHR², where R² therein, independently of one another, may behydrogen, methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl,sec-butyl or tert-butyl.

These are preferably diols or polyols, such as hydrocarbondiols having 2to 20 carbon atoms, e.g. ethylene glycol, 1,2-propanediol,1,3-propanediol, 1,1-dimethylethane-1,2-diol, 1,6-hexanediol,1,10-decanediol, bis-(4-hydroxycyclohexane)isopropylidene,tetramethylcyclobutanediol, 1,2-, 1,3- or 1,4-cyclohexanediol,cyclooctanediol, norbornanediol, pinanediol, decalindiol, etc., estersthereof with short-chain dicarboxylic acids, such as adipic acid orcyclohexanedicarboxylic acid, carbonates thereof, prepared by reactionof the diols with phosgene or by transesterification with dialkyl ordiaryl carbonates, or aliphatic diamines, such as methylene- andisopropylidenebis(cyclohexylamine), piperazine, 1,2-, 1,3- or1,4-diaminocyclohexane, 1,2-, 1,3- or 1,4-cyclohexanebis(methylamine),etc., dithiols or polyfunctional alcohols, secondary or primary aminoalcohols, such as ethanolamine, diethanolamine, monopropanolamine,dipropanolamine, etc., or thioalcohols, such as thioethylene glycol.

Diethylene glycol, triethylene glycol, dipropylene glycol, tripropyleneglycol, neopentylglycol, pentaerythritol, 1,2- and 1,4-butanediol,1,5-pentanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol, 1,2-,1,3- and 1,4-dimethylolcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane,glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane,dipentaerythritol, ditrimethylolpropane, erythritol and sorbitol,2-aminoethanol, 3-amino-1-propanol, 1-amino-2-propanol or2-(2-aminoethoxy)ethanol, bisphenol A or butanetriol are furthermoreconceivable.

Unsaturated polyetherols or polyesterols or polyacrylatepolyols havingan average OH functionality of 2 to 10, and polyamines, such as, forexample, polyethylenimine, or polymers of, for example,poly-N-vinylformamide which comprise free amino groups, are furthermoresuitable.

The cycloaliphatic diols, such as, for example,bis-(4-hydroxycyclohexane)-isopropylidene, tetramethylcyclobutanediol,1,2-, 1,3- or 1,4-cyclohexanediol, cyclooctanediol or norbornanediol,are particularly suitable here.

The polyurethanes which can be used according to the invention areobtained by reacting the components (a), (b) and (c) with one another.

The molar composition (a):(b):(c) per 3 mol of reactive isocyanategroups in (a) is as a rule as follows:

-   (b) 1.5-3.0, preferably 1.5-2.5, particularly preferably 1.5-2.0 and    in particular 1.6-1.8 mol of groups reactive toward isocyanate and-   (c) 0-1.5, preferably 0.5-1.5, particularly preferably 0.7-1.5 and    in particular 0.8-1.5 mol of groups reactive toward isocyanate.

With the use of the polyurethanes in aqueous systems, preferablysubstantially all isocyanate groups present have reacted.

The formation of the adduct from the compound containing isocyanategroups and the compound which comprises groups reactive towardisocyanate groups is effected, as a rule, by mixing the components inany desired sequence, if appropriate at elevated temperature.

Preferably, the compound which comprises groups reactive towardisocyanate groups is added to the compound containing isocyanate groups,preferably in a plurality of steps.

Particularly preferably, the compound containing isocyanate groups isinitially taken and the compounds which comprise groups reactive towardisocyanate are added. In particular, the compound (a) containingisocyanate groups is initially taken and then (b) is added. Ifappropriate, desired further components can subsequently be added.

As a rule, the reaction is carried out at temperatures between 5 and100° C., preferably between 20 and 90° C. and particularly preferablybetween 40 and 80° C. and in particular between 60 and 80° C.

The procedure is preferably carried out under anhydrous conditions.

Here, anhydrous means that the water content in the reaction system isnot more than 5% by weight, preferably not more than 3% by weight andparticularly preferably not more than 1% by weight.

In order to suppress polymerization of the polymerizable double bonds,the procedure is preferably carried out under an oxygen-containing gas,particularly preferably air or air-nitrogen mixtures.

Air or a mixture of oxygen or air and a gas which is inert under theconditions of use can preferably be used as the oxygen-containing gas.Nitrogen, helium, argon, carbon monoxide, carbon dioxide, steam, lowerhydrocarbons or mixtures thereof can be used as the inert gas.

The oxygen content of the oxygen-containing gas may be, for example,from 0.1 to 22% by volume, preferably from 0.5 to 20, particularlypreferably from 1 to 15, very particularly preferably from 2 to 10 andin particular from 4 to 10% by volume. If desired, higher oxygencontents can of course also be used.

The reaction can also be carried out in the presence of an inertsolvent, e.g. acetone, isobutyl methyl ketone, toluene, xylene, butylacetate or ethoxyethyl acetate. However, the reaction is preferablycarried out in the absence of a solvent.

The urethane (meth)acrylates preferably have a number average molecularweight M_(n) from 1000 to 20 000, in particular from 1000 to 10 000,particularly preferably from 1000 to 4000, g/mol (determined by gelpermeation chromatography using tetrahydrofuran and polystyrene asstandard).

The urethane (meth)acrylates preferably contain from 1 to 5,particularly preferably from 2 to 4, mol of (meth)acrylate groups per1000 g of urethane (meth)acrylate. The urethane vinyl ethers preferablycontain from 1 to 5, particularly preferably from 2 to 4, mol of vinylether groups per 1000 g of urethane vinyl ether.

In a preferred embodiment of this invention, the urethane(meth)acrylates or urethane vinyl ethers, preferably urethane acrylates,comprise at least one cycloaliphatic isocyanate, i.e. a compound inwhich at least one isocyanate group is bonded to a cycloaliphatic, as acomponent, particularly preferably IPDI.

In a further preferred embodiment, compounds used are those as describedin WO 00/39183, page 4, line 3 to page 10, line 19, the disclosure ofwhich is hereby incorporated by reference. Particularly preferred amongthese are those compounds which have, as components, at least one(cyclo)aliphatic isocyanate having allophanate groups and at least onehydroxyalkyl (meth)acrylate, very particularly preferably product No. 1to 9 in table 1 on page 24 of WO 00/39183.

Other suitable radiation-curable compounds are carbonate (meth)acrylateswhich comprise on average preferably from 1 to 5, in particular from 2to 4, particularly preferably 2 or 3, (meth)acrylate groups and veryparticularly preferably 2 (meth)acrylate groups.

The number average molecular weight M_(n) of the carbonate(meth)acrylates is preferably from 2000 to 3000 g/mol (determined by gelpermeation chromatography using polystyrene as a standard andtetrahydrofuran as a solvent).

The carbonate (meth)acrylates are obtainable in a simple manner bytransesterification of carbonic esters with polyhydric, preferablydihydric, alcohols (diols, e.g. hexanediol) and subsequentesterification of the free OH groups with (meth)acrylic acid, ortransesterification with (meth)acrylic esters, as described, forexample, in EP-A 92 269. They are also obtainable by reacting phosgene,urea derivatives with polyhydric, e.g. dihydric, alcohols.

In an analogous manner, vinyl ether carbonates are also obtainable byreacting a hydroxyalkyl vinyl ether with carbonic esters and, ifappropriate, dihydric alcohols.

(Meth)acrylates or vinyl ethers of polycarbonatepolyols, such asreaction product of one of said di- or polyols and a carbonic ester orelse a hydroxyl-containing (meth)acrylate or vinyl ether, are alsoconceivable.

Suitable carbonic esters are, for example, ethylene or 1,2- or1,3-propylene carbonate or dimethyl, diethyl or dibutyl carbonate.

Suitable hydroxyl-containing (meth)acrylates are, for example,2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate,1,4-butanediol mono(meth)acrylate, neopentylglycol mono(meth)acrylate,glyceryl mono- and di(meth)acrylate, trimethylolpropane mono- anddi(meth)acrylate and pentaerythrityl mono-, di- and tri(meth)acrylate.

Suitable hydroxyl-containing vinyl ethers are, for example,2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether.

Particularly preferred carbonate (meth)acrylates are those of theformula:

where R is H or CH₃, X is a C₂-C₁₈-alkylene group and n is an integerfrom 1 to 5, preferably from 1 to 3.

R is preferably H and X is preferably C₂- to C₁₀-alkylene, for example1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene or1,6-hexylene, particularly preferably C₄- to C₈-alkylene. Veryparticularly preferably, X is C₆-alkylene.

They are preferably aliphatic carbonate (meth)acrylates.

The polymers i) as such are thermoplastically processible before the UVcuring.

Re ii)

The unsaturated polymers i) can be used as mixtures with ethylenicallyunsaturated, low molecular weight compounds.

In this context, low molecular weight compounds are understood asmeaning compounds having a number average molecular weight of less than2000 g/mol (determined by gel permeation chromatography usingpolystyrene as a standard).

These may be, for example, those compounds mentioned under i) which havea molar mass of less than 2000 g/mol, for example epoxide(meth)acrylates having a molar mass of 340, preferably 500 andparticularly preferably 750 to less than 2000 g/mol, urethane(meth)acrylates having a molar mass of 300, preferably 500 andparticularly preferably 750 to less than 2000 g/mol or carbonate(meth)acrylates having a molar mass of 170, preferably 250 andparticularly preferably 500 to less than 2000 g/mol.

Furthermore suitable are, for example, compounds capable of free radicalpolymerization and having only one ethylenically unsaturated,copolymerizable group.

Examples are C₁-C₂₀-alkyl (meth)acrylates, vinylaromatics having up to20 carbon atoms, vinyl esters of carboxylic acids comprising up to 20carbon atoms, ethylenically unsaturated nitriles, vinyl ethers ofalcohols comprising 1 to 10 carbon atoms and aliphatic hydrocarbonshaving 2 to 20, preferably 2 to 8, carbon atoms and 1 or 2 double bonds.

Preferred alkyl (meth)acrylates are those having a C₁-C₁₀-alkyl radical,such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethylacrylate and 2-ethylhexyl acrylate.

Mixtures of the alkyl (meth)acrylates are also particularly suitable.

Vinyl esters of carboxylic acids having 1 to 20 carbon atoms are, forexample, vinyl laurate, vinyl stearate, vinyl propionate and vinylacetate.

Suitable vinylaromatic compounds are, for example, vinyltoluene,α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferablystyrene.

Examples of nitriles are acrylonitrile and methacrylonitrile.

Suitable vinyl ethers are, for example, vinyl methyl ether, vinylisobutyl ether, vinyl hexyl ether and vinyl octyl ether.

Butadiene, isoprene and ethylene, propylene and isobutylene may bementioned as nonaromatic hydrocarbons having 2 to 20, preferably 2 to 8,carbon atoms and one or two olefinic double bonds.

Compounds capable of free radical polymerization and having a pluralityof ethylenically unsaturated groups are preferred.

These are in particular (meth)acrylate compounds, the acrylatecompounds, i.e. the derivatives of acrylic acid, being preferred in eachcase.

Preferred (meth)acrylate compounds contain 2 to 20, preferably 2 to 10and very particularly preferably 2 to 6 copolymerizable, ethylenicallyunsaturated double bonds.

(Meth)acrylic esters and in particular acrylic esters of polyfunctionalalcohols, in particular those which comprise no further functionalgroups or at least ether groups apart from the hydroxyl groups may bementioned as (meth)acrylate compounds. Examples of such alcohols are,for example, bifunctional alcohols, such as ethylene glycol, propyleneglycol and the members thereof having a higher degree of condensation,for example such as diethylene glycol, triethylene glycol, dipropyleneglycol, tripropylene glycol, etc., butanediol, pentanediol, hexanediol,neopentylglycol, alkoxylated phenolic compounds, such as ethoxylated orpropoxylated bisphenols, cyclohexanedimethanol, trifunctional andhigher-functional alcohols, such as glycerol, trimethylolpropane,trimethylolethane, neopentylglycol, pentaerythritol, glycerol,ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol,1,2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol,neopentylglycol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol,butanetriol, sorbitol, mannitol and the corresponding alkoxylated, inparticular ethoxylated and propoxylated, alcohols.

The alkoxylation products are obtainable in a known manner by reactionof the above alcohols with alkylene oxides, for example ethylene oxide,propylene oxide, butylene oxide, isobutylene oxide and vinyloxirane, inany desired sequence or as a mixture, preferably ethylene oxide and/orpropylene oxide and particularly preferably ethylene oxide. The degreeof alkoxylation per hydroxyl group is preferably from 0 to 10, i.e. 1mol of hydroxyl can preferably be alkoxylated with up to 10 mol ofalkylene oxides.

Polyetheralcohols containing vinyl ether groups are obtained, forexample, in a corresponding manner by reaction of hydroxyalkyl vinylethers with alkylene oxides.

Polyetheralcohols containing (meth)acrylic acid groups can be obtained,for example, by transesterification of (meth)acrylic esters with thepolyetheralcohols, by esterification of the polyetheralcohols with(meth)acrylic acid or by use of hydroxyl-containing (meth)acrylates asdescribed above under (b).

Preferred polyetheralcohols are polyethylene glycols having a molar massbetween 106 and 2000, preferably between 106 and 898, particularlypreferably between 238 and 678.

Poly-THF having a molar mass between 162 and 2000 andpoly-1,3-propanediol having a molar mass between 134 and 1178 canfurthermore be used as polyetheralcohols.

Polyester (meth)acrylates may furthermore be mentioned as (meth)acrylatecompounds, these being the (meth)acrylic esters of polyesterols.

Polyesterpolyols are known, for example, from Ullmanns Enzyklopädie dertechnischen Chemie, 4th Edition, Volume 19, pages 62 to 65.Polyesterpolyols which are obtained by reacting dihydric alcohols withdibasic carboxylic acids are preferably used. Instead of the freepolycarboxylic acids, it is also possible to use the correspondingpolycarboxylic anhydrides or corresponding polycarboxylic esters oflower alcohols or mixtures thereof for the preparation of thepolyesterpolyols. The polycarboxylic acids may be aliphatic,cycloaliphatic, araliphatic, aromatic, heterocyclic and, if appropriate,may be, for example, substituted by halogen atoms and/or unsaturated.The following may be mentioned as examples of these:

oxalic acid, maleic acid, fumaric acid, succinic acid, glutaric acid,adipic acid, sebacic acid, dodecanedioic acid, o-phthalic acid,isophthalic acid, terephthalic acid, trimellitic acid, azelaic acid,1,4-cyclohexanedicarboxylic acid or tetrahydrophthalic acid, subericacid, azelaic acid, phthalic anhydride, tetrahydrophthalic anhydride,hexahydrophthalic anhydride, tetrachlorophthalic anhydride,endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleicanhydride, dimeric fatty acids, the isomers and hydrogenation productsthereof and esterifiable derivatives, such as anhydrides or dialkylesters, for example C₁-C₄-alkyl esters, preferably methyl, ethyl orn-butyl esters, of said acids. Dicarboxylic acids of the general formulaHOOC—(CH₂)_(y)—COOH, where y is a number from 1 to 20, preferably aneven number from 2 to 20, are preferred, succinic acid, adipic acid,sebacic acid and dodecanedicarboxylic acid being particularly preferred.

Suitable polyhydric alcohols for the preparation of the polyesterols are1,2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol,1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol,3-methylpentane-1,5-diol, 2-ethylhexane-1,3-diol,2,4-diethyloctane-1,3-diol, 1,6-hexanediol, poly-THF having a molar massbetween 162 and 2000, poly-1,3-propanediol having a molar mass between134 and 1178, poly-1,2-propanediol having a molar mass between 134 and898, polyethylene glycol having a molar mass between 106 and 458,neopentylglycol, neopentylglycol hydroxypivalate,2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol,2,2-bis(4-hydroxycyclohexyl)propane, 1,1-, 1,2-, 1,3- and1,4-cyclohexanedimethanol, 1,2-, 1,3- or 1,4-cyclohexanediol,trimethlyolbutane, trimethylolpropane, trimethylolethane,neopentylglycol, pentaerythritol, glycerol, ditrimethylolpropane,dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol,adonitol (ribitol), arabitol (lyxitol), xylitol, dulcitol (galactitol),maltitol or isomaltitol.

Alcohols of the general formula HO—(CH₂)_(x)—OH, where x is a numberfrom 1 to 20, preferably an even number from 2 to 20, are preferred.Ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol anddodecane-1,12-diol are preferred. Neopentylglycol is furthermorepreferred.

Polycarbonatediols, as can be obtained, for example, by reactingphosgene with an excess of the low molecular weight alcohols mentionedas components for the polyesterpolyols are furthermore suitable.

Lactone-based polyesterdiols are also suitable, these being homo- orcopolymers of lactones, preferably adducts of lactones with suitabledifunctional initiator molecules, which adducts have terminal hydroxylgroups. Preferred lactones are those which are derived from compounds ofthe general formula HO—(CH₂)_(z)—COOH, where z is a number from 1 to 20and an H atom of a methylene unit may also be substituted by a C₁- toC₄-alkyl radical. Examples are ε-caprolactone, β-propiolactone,gamma-butyrolactone and/or methyl-ε-caprolactone, 4-hydroxybenzoic acid,6-hydroxy-2-naphthalenecarboxylic acid or pivalolactone and mixturesthereof. Suitable initiator components are, for example, the lowmolecular weight dihydric alcohols mentioned above as a component forthe polyesterpolyols. The corresponding polymers of E-caprolactone areparticularly preferred. Lower polyesterdiols or polyetherdiols can alsobe used as initiators for the preparation of the lactone polymers.Instead of the polymers of lactones, it is also possible to use thecorresponding, chemically equivalent polycondensates of thehydroxycarboxylic acids corresponding to the lactones.

Polyester (meth)acrylates can be prepared in a plurality of stages or inone stage, as described, for example, in EP 279 303, from acrylic acid,polycarboxylic acid and polyol.

Re iii)

Suitable saturated thermoplastic polymers are, for example, polymethylmethacrylate, polystyrene, impact-resistant polymethyl methacrylate,high-impact polystyrene, polycarbonate and polyurethanes.

The radiation curability is ensured by the addition of an ethylenicallyunsaturated, radiation-curable compound. This may be one of thecompounds mentioned under i) and/or ii).

The binders (based on the solids content, i.e. without the presence ofsolvents) have, as a rule, the following composition:

-   i) at least 20% by weight, preferably at least 30% by weight,    particularly preferably at least 50, very particularly preferably at    least 60, in particular at least 75 and especially at least 80% by    weight and up to 100% by weight, preferably up to 98% by weight,    particularly preferably up to 95, very particularly preferably up to    90 and in particular up to 85% by weight,-   ii) for example, up to 70% by weight, preferably up to 50% by    weight, particularly preferably up to 25% by weight, very    particularly preferably up to 10, in particular up to 5% by weight    and especially 0% by weight,-   iii) for example, up to 50% by weight, preferably up to 25% by    weight, particularly preferably up to 10% by weight, very    particularly preferably up to 5% by weight and in particular 0% by    weight,    -   with the proviso that the sum is always 100% by weight.

A substantial feature of the binder i) to iii) is that the glasstransition temperature (T_(g)) of the binder is below 50° C., preferablybelow 20° C., particularly preferably below 10° C. In general, the T_(g)does not fall below a value of −60° C. (The data relate to the binderbefore the radiation curing.)

The glass transition temperature T_(g) of the binder is determined bythe DSC method (differential scanning calorimetry) according to ASTM3418/82.

According to the invention, the amount of the curable, i.e.ethylenically unsaturated, groups is more than 2 mol/kg, preferably morethan 2 mol/kg to 8 mol/kg, particularly preferably at least 2.1 mol/kgto 6 mol/kg, very particularly preferably 2.2 to 6, in particular 2.3 to5 and especially 2.5 to 5 mol/kg of the binder (solid), i.e. withoutwater or other solvents.

The binder (with solvent present if appropriate) preferably has aviscosity of from 0.02 to 100 Pa·s at 25° C. (determined in a rotationalviscometer).

In a preferred embodiment of the present invention, theradiation-curable material according to the invention comprises not morethan 10% by weight of compounds which have only one curable group,preferably not more than 7.5% by weight, particularly preferably notmore than 5% by weight, very particularly preferably not more than 2.5%by weight, in particular not more than 1% by weight and especially 0% byweight. In the radiation-curable materials according to the invention,the use of compounds having two or more curable groups leads to anincreased crosslinking density, which leads to positive coatingproperties, such as scratch resistance, hardness and/or resistance tochemicals.

The radiation-curable materials may comprise further components. Inparticular, photoinitiators, leveling agents and stabilizers may bementioned. In exterior applications, i.e. for coatings which are exposeddirectly to daylight, the materials contain in particular UV absorbersand free radical scavengers.

For example, tin octanoate, zinc octanoate, dibutyltin laurate or diaza[2.2.2]-bicyclooctane, can be used as accelerators for the thermalpostcuring.

Photoinitiators may be, for example, photoinitiators known to the personskilled in the art, for example those mentioned in “Advances in PolymerScience”, Volume 14, Springer Berlin 1974 or in K. K. Dietliker,Chemistry and Technology of UV- and EB-Formulation for Coatings, Inksand Paints, Volume 3; Photoinitiators for Free Radical and CationicPolymerization, P. K. T. Oldring (Eds), SITA Technology Ltd, London.

For example, mono- or bisacylphosphine oxides, as described, forexample, in EP-A 7 508, EP-A 57 474, DE-A 196 18 720, EP-A 495 751 orEP-A 615 980 are suitable, for example2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin® TPO from BASFAG), ethyl-2,4,6-trimethylbenzoylphenylphosphinate (Lucirin® TPO L fromBASF AG), bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure®819 from Ciba Spezialitätenchemie), benzophenones, hydroxyacetophenones,phenylglyoxylic acid and its derivatives or mixtures of thesephotoinitiators. Benzophenone, acetophenone, acetonaphthoquinone, methylethyl ketone, valerophenone, hexanophenone, α-phenylbutyrophenone,p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone,4-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone,4′-methoxyacetophenone, β-methylanthraquinone, tert-butylanthraquinone,anthraquinonecarboxylic esters, benzaldehyde, α-tetralone,9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone,3-acetylphenanthrene, 3-acetylindole, 9-fluorenone, 1-indanone,1,3,4-triacetylbenzene, thioxanthen-9-one, xanthen-9-one,2,4-dimethylthioxanthone, 2,4-diethylthioxanthone,2,4-diisopropylthioxanthone, 2,4-dichlorothioxanthone, benzoin, benzoinisobutyl ether, chloroxanthenone, benzoin tetrahydropyranyl ether,benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoinisopropyl ether, 7-H-benzoin methyl ether, benz[de]anthracen-7-one,1-naphthaldehyde, 4,4′-bis(dimethylamino)benzophenone,4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone,1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-1-ol,2-hydroxy-2,2-dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone,2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone,1-hydroxyacetophenone, acetophenone dimethyl ketal,o-methoxybenzophenone, triphenylphosphine, tri-o-tolylphosphine,benz[a]anthracene-7,12-dione, 2,2-diethoxyacetophenone, benzil ketals,such as benzil dimethyl ketal,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,anthraquinones, such as 2-methylanthraquinone, 2-ethylanthraquinone,2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinoneand 2,3-butanedione may be mentioned by way of example.

Non-yellowing or slightly yellowing photoinitiators of thephenylglyoxalic ester type, as described in DE-A 198 26 712, DE-A 199 13353 or WO 98/33761 are also suitable.

UV absorbers convert UV radiation into heat energy. Known UV absorbersare hydroxybenzophenones, benzotriazoles, cinnamic esters andoxalanilides.

Free radical scavengers bind free radicals formed as intermediates.Important free radical scavengers are sterically hindered amines, whichare known as HALS (hindered amine light stabilizers).

For exterior applications, the total content of UV absorbers and freeradical scavengers is preferably from 0.1 to 5 parts by weight,particularly preferably from 0.5 to 4 parts by weight, based on 100parts by weight of the radiation-curable compounds.

Otherwise, in addition to radiation-curable compounds, theradiation-curable materials may also comprise compounds which contributeto the curing through other chemical reactions. For example,polyisocyanates which crosslink with hydroxyl or amino groups aresuitable.

The radiation-curable materials may be present in anhydrous andsolvent-free form, as a solution or as a dispersion.

Anhydrous and solvent-free radiation-curable materials or aqueoussolutions or aqueous dispersions are preferred.

Anhydrous and solvent-free, radiation-curable materials are particularlypreferred.

The radiation-curable material can be molded by a thermoplastic methodand can be extruded.

The above radiation-curable materials form the top layer. The layerthickness (after drying and curing) is preferably from 10 to 100 μm.

Substrate Layer

The substrate layer serves as a base and is intended to ensure apermanently high toughness of the overall laminate.

The substrate layer preferably consists of a thermoplastic polymer, inparticular polymethyl methacrylates, polybutyl methacrylates,polyethylene terephthalates, polybutylene terephthalates, polyvinylidenefluorides, polyvinyl chlorides, polyesters, polyolefins,acrylonitrile-ethylene-propylene-diene-styrene copolymers (A-EPDM),polyetherimides, polyetherketones, polyphenylene sulfides, polyphenyleneethers or mixtures thereof.

Polyethylene, polypropylene, polystyrene, polybutadiene, polyester,polyamides, polyether, polycarbonate, polyvinylacetal,polyacrylonitrile, polyacetal, polyvinyl alcohol, polyvinyl acetate,phenol resins, urea resins, melamine resins, alkyd resins, epoxy resinsor polyurethanes, the block or graft copolymers thereof and blendsthereof may furthermore be mentioned.

ABS, AES, AMMA, ASA, EP, EPS, EVA, EVAL, HDPE, LDPE, MABS, MBS, MF, PA,PA6, PA66, PAN, PB, PBT, PBTP, PC, PE, PEC, PEEK, PEI, PEK, PEP, PES,PET, PETP, PF, PI, PIB, PMMA, POM, PP, PPS, PS, PSU, PUR, PVAC, PVAL,PVC, PVDC, PVP, SAN, SB, SMS, UF, UP plastics (abbreviation according toDIN 7728) and aliphatic polyketones may preferably be mentioned.

Particularly preferred substrates are polyolefins, such as, for example,PP (polypropylene), which optionally may be isotactic, syndiotactic oratactic and optionally may be unoriented or oriented by uniaxial orbiaxial stretching, SAN (styrene-acrylonitrile copolymers), PC(polycarbonates), PMMA (polymethyl methacrylates), PBT (poly(butyleneterephthalate)s), PA (polyamides), ASA (acrylonitrile-styrene-acrylatecopolymers) and ABS (acrylonitrile-butadiene-styrene copolymers) and theblends thereof. PP, SAN, ABS, ASA and blends of ABS or ASA with PA orPBT or PC are particularly preferred.

ASA, in particular according to DE 19 651 350, and the blend ASA/PC arevery particularly preferred. Polymethyl methacrylate (PMMA) or toughenedPMMA is likewise preferred.

The layer thickness is preferably from 50 μm to 5 mm. From 100 to 1000μm, in particular from 100 to 500 μm, is particularly preferred,especially if the back of the substrate layer is sprayed.

The polymer of the substrate layer may comprise additives. Fillers orfibers are particularly suitable. The substrate layer may also becolored and thus simultaneously serve as a color-imparting layer.

Further Layers

In addition to the top layer and the substrate layer, the film maycomprise further layers.

For example, color-imparting intermediate layers or further layers ofthermoplastic material (thermoplastic intermediate layers) whichstrengthen the film or serve as release layers, as disclosed, forexample, in WO 2004/009251, are suitable.

Thermoplastic intermediate layers may consist of the polymers mentionedabove under substrate layer.

Polymethyl methacrylate (PMMA), preferably toughened PMMA, isparticularly preferred. Polyurethane may also be mentioned.

Color-imparting layers can likewise consist of said polymers.

They comprise dyes or pigments which are distributed in the polymerlayer.

A preferred film has, for example, the following layer structure, thealphabetic sequence corresponding to the spatial arrangement:

A) Top layerB) Thermoplastic intermediate layer (optional)C) Color-imparting intermediate layer (optional)D) Substrate layerE) Adhesive layer (optional)

An adhesive layer may be applied to the back of the substrate layer(i.e. the side facing the object with which lamination is to beeffected) if the film is to be adhesively bonded to the substrate.

A protective layer, for example a peelable film which preventsunintentional curing, can be applied to the transparent top layer. Thethickness may be, for example, from 50 to 100 μm. The protective layermay consist of, for example, polyethylene or polyterephthalate. Theprotective layer can be removed prior to irradiation.

However, the irradiation can also be effected through the protectivelayer, and for this purpose the protective layer must be transparent inthe wavelength range of the irradiation.

The total thickness of the film is preferably from 50 to 1000 μm.

Production of the laminated sheet or film

A laminate comprising the layers B) to D) can be produced, for example,by coextrusion of all or some of the layers.

For the coextrusion, the individual components are rendered flowable inextruders and are brought into contact with one another by means ofspecial apparatuses so that the films having the layer sequencedescribed above result. For example, the components can be coextrudedthrough a sheet die. This method is explained in EP-A2-0 225 500. Inaddition to the methods described there, adapter coextrusion can also beused.

The laminate can be produced by conventional methods, for example bycoextrusion, as described above, or by lamination of the layers, forexample in a heatable nip. First, a laminate of the layers with theexception of the top layer can be produced in this manner, and the toplayer can then be applied by conventional methods.

In the extrusion (including coextrusion) of the radiation-curablematerials, the preparation of the radiation-curable material by mixingof the components and the production of the top layer can be effected inone operation.

For this purpose, thermoplastic components, for example unsaturatedpolymers i) or saturated polymers under iii) (see above) can first bemelted in the extruder. The necessary melting point depends on therespective polymer. Preferably after the melting process, the furthercomponents, in particular radiation-curable, low molecular weightcompounds ii) (see above) can be metered in. The compounds act asplasticizers so that the temperature at which the material is present asa melt decreases. The temperature during addition of theradiation-curable compound must in particular be below a criticaltemperature at which thermal curing of the radiation-curable compoundtakes place.

The critical temperature can readily be determined by a calorimetricmeasurement, i.e. of the heat absorption with increasing temperature,corresponding to the above-described determination of the glasstransition temperature.

The radiation-curable material is then extruded directly as a top layeronto the existing laminate or, in the case of coextrusion, with layersof the laminate. By means of the extrusion, the laminated sheet or filmis directly obtained.

The radiation-curable material can preferably be applied to thesubstrate layer or to the laminate in a simple manner, for example byspraying, trowelling, knife coating, brushing, rolling, roll-coating,pouring, lamination, etc., and, if appropriate, can be dried.

The top layer is resistant to blocking, i.e. it is not tacky, and isradiation-crosslinkable. The laminated sheet or film can be molded by athermoplastic method. If desired, a protective layer (protective film)can be placed on the top layer directly after the production of thelaminated sheet or film.

The laminated sheet or film has high gloss and good mechanicalproperties. Tearing is scarcely observable.

The extensibility of the laminated sheet or film is preferably at least100%, based on the unextended state (at 140° C. at a thickness of 30μm).

Methods of Use

The film can be stored without partial curing (as described in EP-A2 819516) until subsequent use.

Adhesion or deterioration of the performance characteristics beforesubsequent use is not observed or scarcely observed.

The film is preferably used as a laminating material.

Preferably, the lamination of the substrate is first effected and thenthe curing of the top layer by radiation.

The lamination can be effected by adhesive bonding of the film to thesubstrates. For this purpose, the film is provided on the back of thesubstrate layer, preferably with the adhesive layer E. Suitablesubstrates are those of wood, plastic or metal.

The lamination can also be effected by spraying the back of the film.For this purpose, the film is preferably thermoformed in a thermoformingmold and the back of the substrate layer sprayed with a plasticsmaterial. The plastics material comprises, for example, polymers whichwere mentioned above in the description of the substrate layer or, forexample, polyurethane, in particular polyurethane foam. The polymers maycomprise additives, in particular, for example, fibers, such as glassfibers, or fillers.

The radiation curing of the top layer is preferably effected after thethermoforming process and particularly preferably after the spraying ofthe back of the film.

The radiation curing is effected by means of high-energy light, e.g. UVlight or electron beams. The radiation curing can be effected atrelatively high temperatures. A temperature above the T_(g) of theradiation-curable binder is preferred.

Here, radiation curing means the free radical polymerization ofpolymerizable compounds caused by electromagnetic and/or corpuscularradiation, preferably UV light in the wavelength range of λ=200 to 700nm or electron radiation in the range of 150 to 300 keV and particularlypreferably with a radiation dose of at least 80, preferably from 80 to3000, mJ/cm².

In addition to radiation curing, further curing mechanisms may also beinvolved, for example thermal, moisture, chemical and/or oxidativecuring.

The laminating materials can be applied once or several times by a verywide range of spraying methods, such as, for example, air pressure,airless or electrostatic spraying methods with the use of one- ortwo-component spraying units, but also by spraying, trowelling, knifecoating, brushing, rolling, roll-coating, pouring, lamination, sprayingof the back or coextrusion.

The coat thickness is as a rule in the range from about 3 to 1000 g/m²and preferably from 10 to 200 g/m².

The drying and curing of the coatings is generally effected understandard temperature conditions, i.e. without heating of the coating.However, the mixtures according to the invention can also be used forthe production of coatings which, after application, are dried and curedat elevated temperature, for example at 40-250° C., preferably 40-150°C. and in particular at 40-100° C. This is limited by the heat stabilityof the substrate.

Furthermore, a process for the coating of substrates is disclosed, inwhich the coating material according to the invention or coatingformulations comprising it, to which, if appropriate, heat-curableresins have been added, is or are applied to the substrate, dried andthen cured by means of electron beams or UV exposure under anoxygen-containing atmosphere or preferably under inert gas, ifappropriate at temperatures up to the drying temperature.

The process for the coating of substrates can also be carried out insuch a way that, after the application of the coating material accordingto the invention or coating formulations, irradiation with electronbeams or UV light under oxygen or preferably under inert gas is firsteffected in order to achieve preliminary curing, a thermal treatment issubsequently effected at temperatures of up to 160° C., preferablybetween 60 and 160° C., and final curing is then effected by means ofelectron beams or UV light under oxygen or preferably under inert gas.

If a plurality of layers of the laminating material are applied one ontop of the other, drying and/or radiation curing can, if appropriate, beeffected after each laminating process.

Suitable radiation sources for the radiation curing are, for example,low-pressure mercury lamps, medium-pressure mercury lamps withhigh-pressure lamps and fluorescent tubes, pulsed lamps, metal halidelamps, electron flash apparatuses, which permit radiation curing withouta photoinitiator, or excimer lamps. Radiation curing is effected by theaction of high-energy radiation, i.e. UV radiation or daylight,preferably light in the wavelength range of λ=200 to 700 nm,particularly preferably of λ=200 to 500 nm and very particularlypreferably of λ=250 to 400 nm, or by irradiation with high-energyelectrons (electron radiation; 150 to 300 keV). Radiation sources usedare, for example, high-pressure mercury vapor lamps, lasers, pulsedlamps (flashlight), halogen lamps or excimer lamps. The radiation doseusually sufficient for crosslinking in the case of UV curing is in therange from 80 to 3000 mJ/cm².

Of course, a plurality of radiation sources can also be used for thecuring, e.g. two to four.

These may also emit in respect of different wavelength ranges.

The drying and/or thermal treatment can also be effected in addition toor instead of the thermal treatment by NIR radiation, NIR radiationbeing defined here as electro-magnetic radiation in the wavelength rangefrom 760 nm to 2.5 μm, preferably from 900 to 1500 nm.

The irradiation can, if appropriate, also be carried out in the absenceof oxygen, for example under an inert gas atmosphere. Suitable inertgases are preferably nitrogen, noble gases, carbon dioxide or combustiongases. Furthermore, the irradiation can be effected by covering thelaminating material with transparent media. Transparent media are, forexample, plastics films, glass or liquids, e.g. water. Irradiation inthe manner described in DE-A1 199 57 900 is particularly preferred.

If crosslinking agents which effect additional thermal crosslinking,e.g. isocyanates, are also present, the thermal crosslinking can becarried out, for example, simultaneously or after the radiation curing,by increasing the temperature to 150° C., preferably to 130° C.

Fields of Use and Advantages

The films can be used for laminating moldings. Any desired moldings aresuitable. Particularly preferably, the films are used for laminatingmoldings in which very good surface properties, high resistance toweathering and good UV resistance are important. The surfaces obtainedare moreover very scratch-resistant and have good adhesive strength sothat destruction of the surfaces by scratching or delamination of thesurfaces is reliably prevented. Thus, moldings for exterior use outsidebuildings constitute a preferred field of use. In particular, the filmsare used for the lamination of automotive parts, for example fenders,door trims, bumpers, spoilers, skirts as well as exterior mirrors beingsuitable.

An advantage of the present invention is that the coating materialsaccording to the invention have great hardness in combination with highresilience, depending on the composition, which makes such coatingmaterials particularly suitable for finishes which are exposed to highstresses and which nevertheless must not flake. Examples of these arefinishes on bumpers, spoilers or door sills.

Other compositions according to the invention have extremely highhardness in combination with acceptable resilience, which makes themparticularly suitable for finishes over large areas which are subject tolittle stress, such as, for example, in car roofs, engine hoods ordoors. ppm and percentages used this document relate to percentages byweight and ppm by weight, unless stated otherwise.

The examples which follow are intended to illustrate the invention butnot to restrict it to these examples.

EXAMPLES The Following Compounds were Used

Isocyanurate (Basonat® HI 100 from BASF): polyisocyanate (isocyanurate)based on hexamethylene diisocyanate with an NCO content according to DINEN ISO 11909 of from 21.5 to 22.5%

Biuret (Basonat® HB 100 from BASF): polyisocyanate (biuret) based onhexamethylene diisocyanate with an NCO content according to DIN EN 11909of from 22 to 23%

Isocyanurate (Vestanat® T 1890 from Degussa): polyisocyanate(isocyanurate) based on isophorone diisocyanate with an NCO contentaccording to DIN EN ISO 11909 of from 11.7 to 12.3%

Lupraphen® VP 9327: polyesterol from BASF AG comprising adipicacid/cyclohexanedimethanol/isophthalic acid, having an average molarmass of 800 g/mol

Pentaerythrityl tri/tetraacrylate mixture, commercial product from UCB,OH number 103 mg KOH/g

Allophanate obtained from hexamethylene diisocyanate and hydroxyethylacrylate, described in WO 00/39183, page 24, table 1.

Example 1

Bis-(4-hydroxycyclohexane)isopropylidene and Lupraphen® VP 9327 werecoarsely dispersed in hydroxyethyl acrylate and pentaerythrityltri/tetraacrylate at 60° C. with stirring. The isocyanates, hydroquinonemonomethyl ether, 1,6-di-tert-butyl-para-cresol and butyl acetate wereadded to this suspension. After the addition of dibutyltin dilaurate,the batch warmed up. At an internal temperature of 75° C., stirring waseffected for several hours until the NCO value of the reaction mixtureshowed virtually no further change. Methanol was then added until an NCOvalue of 0% was reached.

The composition was as follows:

Bis-(4-hydroxycyclo- 94.88 g (30 mol % of OH) hexane)isopropylideneLupraphen ® VP 9327 105.50 g (10 mol % of OH) Hydroxyethyl acrylate79.75 g (27.5 mol % of OH) Pentaerythrityl tri/tetraacrylate 389.13 g(27.5 mol % of OH) Isocyanurate (based on HDI) 262.08 g (55 mol % ofNCO) Isocyanurate (based on IPDI) 273.15 g (45 mol % of NCO)Hydroquinone monomethyl ether 0.602 g (0.05% based on solid)1,6-Di-tert-butyl-para-cresol 1.204 g (0.1% based on solid) Butylacetate 516.21 g (70% solids) Dibutyltin dilaurate 0.241 g (0.02% basedon solid) Methanol 10.65 g (5 mol % of OH)

Properties of the Uncured Binder:

Tg=18.3° C., η=40-50 Pa·s/RT, double bond density=2.56 mol/kg (100%)

Properties of the Cured Clear Coat:

Relative residual gloss 57.40% according to AMTEC-Kistler test method

Example 2

Bis-(4-hydroxycyclohexane)isopropylidene was coarsely dispersed inhydroxyethyl acrylate and pentaerythrityl tri/tetraacrylate at 60° C.with stirring. The isocyanates, hydroquinone monomethyl ether,1,6-di-tert-butyl-para-cresol and butyl acetate were added to thissuspension. After the addition of dibutyltin dilaurate, the batch warmedup. At an internal temperature of 75° C., stirring was effected forseveral hours until the NCO value of the reaction mixture showedvirtually no further change. Methanol was then added until an NCO valueof 0% was reached.

Bis-(4-hydroxycyclo- 63.25 g (40 mol % of OH) hexane)isopropylideneHydroxyethyl acrylate 39.88 g (27.5 mol % of OH) Pentaerythrityltri/tetraacrylate 194.81 g (27.5 mol % of OH) Isocyanurate (based onHDI) 89.34 g (37.5 mol % of NCO) Biuret (based on HDI) 92.87 g (37.5 mol% of NCO) Isocyanurate (based on IPDI) 75.88 g (25 mol % of NCO)Hydroquinone monomethyl ether 0.278 g (0.05% based on solid)1,6-Di-tert-butyl-para-cresol 0.556 g (0.1% based on solid) Butylacetate 238.30 g (70% solids) Dibutyltin dilaurate 0.222 g (0.04% basedon solid) Methanol 4.46 g (5 mol % of OH)

Properties of the Uncured Binder:

T_(g)=13.2° C., η=47 Pa·s/RT, double bond density=2.8 mol/kg (100%)

Properties of the Cured Clear Coat:

Relative residual gloss 57.00% according to AMTEC-Kistler test method

Example 3

Bis-(4-hydroxycyclohexane)isopropylidene was coarsely dispersed inhydroxyethyl acrylate and pentaerythrityl tri/tetraacrylate at 60° C.with stirring. The isocyanates, hydroquinone monomethyl ether,1,6-di-tert-butyl-para-cresol and butyl acetate were added to thissuspension. After the addition of dibutyltin dilaurate, the batch warmedup. At an internal temperature of 75° C., stirring was effected forseveral hours until the NCO value of the reaction mixture showedvirtually no further change. Methanol was then added until an NCO valueof 0% was reached.

Bis-(4-hydroxycyclohexane)isopropylidene 40 mol % of OH Hydroxyethylacrylate 27.5 mol % of OH Pentaerythrityl tri/tetraacrylate 27.5 mol %of OH Allophanate from HDI and HEA 55 mol % of NCO Isocyanurate (basedon IPDI) 45 mol % of NCO Hydroquinone monomethyl ether 0.05% based onsolid 1,6-Di-tert-butyl-para-cresol 0.1% based on solid Butyl acetate70% solids Dibutyltin dilaurate 0.04% based on solid Methanol 5 mol % ofOH

Properties of the Uncured Binder:

Tg=11.3° C., η=6.6 Pa·s/RT, double bond density (theoretical)=4.41mol/kg (100%)

Double bond density (theoretical)=4.41 mol/kg (100%)

Double bond density (hydrogenation iodine number)=77 g of iodine/100 g(corresponds to 3.03 mol/kg (70%),

therefore 4.33 mol/kg (100%))

For the determination of the hydrogenation iodine number, a sample wasdissolved in glacial acetic acid and hydrogenated at 30° C. and overBaSO₄-supported palladium. The iodine number and the double bond densityare calculated from the hydrogen absorption.

Properties of the Cured Clear Coat:

Relative residual gloss 52.6% according to AMTEC-Kistler test method

Comparative Example

Example 1 from WO 00/63015 was reworked and the relative residual glossvalue was determined.

Not more than 35% were measured.

Use Examples

Determination of the performance characteristics of pendulum damping,Erichsen cupping and scratch resistance

The determination of the pendulum damping was effected analogously toDIN 53157. For this purpose, the radiation-curable compositions wereapplied to glass with a wet film thickness of 400 μm. The wet films weredried in air for 15 minutes at room temperature and then dried for 20minutes at 100° C. The curing of the films obtained in this manner waseffected on an IST coating unit (type M 40 2×1-R-IR-SLC-So inert) with 2UV lamps (mercury high-pressure lamps type M 400 U2H and type M 400U2HC) and at a conveyor belt speed of 10 m/min under a nitrogenatmosphere (O₂≦500 ppm). The radiation dose was about 1900 mJ/cm². Thependulum damping is a measure of the hardness of the coating. Highvalues indicate great hardness.

The determination of the Erichsen cupping was effected analogously toDIN 53156. For this purpose, the respective formulation according to theinvention was applied by means of a box-type doctor blade with a wetfilm thickness of 200 μm to BONDER plate 132. For curing, exposure waseffected in the manner described above. The Erichsen cupping was thendetermined by pressing a metal ball into the uncoated side of the plate.The Erichsen cupping is a measure of the flexibility and elasticity. Itis stated in millimeters (mm). High values indicate high flexibility.

The determination of the scratch resistance was effected by means of theScotch-Brite test on storage for 7 days in a conditioned room. In theScotch-Brite test, a 3×3 cm silicon carbide modified nonwoven (ScotchBrite SUFN, from 3M) as a test specimen is fastened to a cylinder. Thispresses the nonwoven with 250 g onto the coating and is pneumaticallymoved over the coating. The magnitude of the deflection is 7 cm. After10 or 50 double strokes (DS) the gloss (eight-fold determination) ismeasured analogously to DIN 67530 at an angle of incidence of 20° in themiddle region of the stress. The residual gloss value in percent isobtained from the ratio of gloss after stress to initial gloss. After 50double strokes, a gentle wiping is effected twice with a soft clothimpregnated with cleaner's naphtha and the residual gloss is measuredagain.

The preparation of the radiation-curable material is effected bythorough mixing of 100 parts by weight of the urethane acrylatesobtained under examples 1 to 3 with 4 parts by weight of Irgacure® 184from Ciba Spezialitätenchemie (commercially available photoinitiator).Example I from WO 00/63015 served for comparison.

Example Pendulum damping [s] Erichsen cupping [mm] 1 193 2.0 2 177 4.0 3180 0.9 Comparative example 166 3.3

Residual gloss Residual gloss Residual gloss [%] after Example [%] after10 DS [%] after 50 DS cleaner's naphtha 1 89.2 79.1 82.0 2 88.7 82.083.6 3 94.8 83.3 83.8 Comparative 78.1 59.6 60.8 example

1. A radiation-curable laminated sheet or film comprising at least onesubstrate layer and a top layer consisting of a radiation-curablematerial which comprises a binder having a glass transition temperaturebelow 20° C. and a content of ethylenically unsaturated groups of morethan 2 mol/kg of binder, wherein a color-imparting intermediate layer ispresent between the substrate layer and the top layer.
 2. Theradiation-curable laminated sheet or film according to claim 1, whereina layer of polymethyl methacrylates, polybutyl methacrylates,polyethylene terephthalates, polybutylene terephthalates, polyvinylidenefluorides, polyvinyl chlorides, polyesters, polyolefins,acrylonitrile-ethylene-propylene-diene-styrene copolymers (A-EPDM),polyetherimides, polyetherketones, polyphenylene sulfides, polyphenyleneethers or mixtures thereof are present between the color-impartingintermediate layer and the top layer.
 3. The radiation-curable laminatedsheet or film according to claim 1, wherein the radiation-curablematerial comprises one or more mixtures selected from the groupconsisting of: a mixture of polymers having ethylenically unsaturatedgroups and a molar mass of more than 2000 g/mol; a mixture of polymershaving ethylenically unsaturated groups and a molar mass of more than2000 g/mol, with ethylenically unsaturated, low molecular weightcompounds having a molar mass of less than 2000 g/mol; and a mixture ofsaturated, thermoplastic polymers with ethylenically unsaturatedcompounds.
 4. The radiation-curable laminated sheet or film according toclaim 1, wherein the radiation-curable material comprises not more than10% by weight of compounds which have only one curable group.
 5. Theradiation-curable laminated sheet or film according to claim 1, whereinthe binder comprises at least one urethane (meth)acrylate whichcomprises at least one cycloaliphatic isocyanate.
 6. Theradiation-curable laminated sheet or film according to claim 1, whereinthe binder comprises at least one urethane (meth)acrylate whichcomprises isophorone diisocyanate or hexamethylene diisocyanate.
 7. Alaminated shaped article obtainable by a process comprising: laminatinga shaped article with a radiation-curable laminated sheet or filmthereby forming a radiation-curable laminated sheet or film, whereinsaid radiation-curable laminated sheet or film comprises at least onesubstrate layer and a top layer, and wherein the top layer consists ofradiation-curable material which comprises a binder having a glasstransition temperature below 20° C. and a content of ethylenicallyunsaturated groups of more than 2 mol/kg of binder; thermoforming theradiation-curable laminated sheet or film in a thermoforming mold;spraying the back of the substrate layer with a plastics material; andradiation curing the top layer either after the thermoforming or afterthe spraying.